To stain a biologic specimen fixed on a glass slide, it is necessary to bring a staining liquid or reagent into contact with the specimen on the slide. For the present purposes it will be understood that the term staining includes application to the specimen of any of various liquids or reagents during a staining process, even if a particular liquid does not itself produce the actual staining.
One means for staining a specimen affixed to a slide is disclosed by the Scharf U.S. Pat. No. 3,132,744 and comprises a disposable package for receiving two slides to be stained. The package is filled with a staining liquid prior to use, and the slides are immersed in the pool of liquid in order to stain the specimens. While the package disclosed by Scharf allows for on site staining of microscopic slides, several disadvantages are also involved. A relatively large quantity of expensive staining liquid is used for the immersion and staining of the two slides, much more than is necessary for the actual staining of the specimens. Moreover, the centrally extending ribs which separate the two slides can disturb a specimen affixed to the face of a slide.
In another known and widely used apparatus for staining slides, the slide is placed horizontally, specimen up, on a rack suspended in a sink. The staining liquid is poured or dripped from a bottle over the slide to flood the specimen. This apparatus also wastes expensive staining liquid, since much more liquid is generally squeezed or dripped than is actually needed for staining. Also, the sink becomes stained and unsightly after a period of time from the overflow liquid. The operator's fingers become stained when the specimen is picked up. When the bottle reagents remain in the sink area for a prolonged period of time, the fluid can deteriorate or become contaminated, intentionally or accidentally. It generally requires from 6 cc to 8 cc of each reagent to perform a specific examination using the above technique.
A less known apparatus comprises a rack in which the slide or slides are vertically placed, and the rack with the slide therein is dipped into a container of staining liquid. This too uses an amount of dye far in excess of that actually necessary for staining, and, where the reagent is used for more than one slide, contamination often occurs. Likewise, this technique involves pouring liquid from bottles into containers and pouring the staining liquid from containers into sinks.
Another less common means is an automated staining device. Large hospitals with heavy workloads are more inclined to use this type of apparatus. The machinery involved in such an automated device is extremely expensive and can only be justified where the amount of staining is extrememly heavy. The cost of such machines prohibits their use in most staining operations. Furthermore, automated staining devices are only available for one or two stains.
In our copending application, Ser. No. 372,591 filed Apr. 28, 1982 for METHOD AND STRUCTURE FOR STAINING BIOLOGIC SLIDES, a single slide with a specimen fixed thereon is inserted vertically, lengthwise, into a confined chamber or cavity formed within a container. The slide is preferably guided and positioned within the chamber on tracks. A thin film of staining liquid is formed on each face of the slide when the slide displaces a quantity of staining liquid at the bottom of the chamber into confined spaces adjacent to the faces of the slide. The volume of staining liquid used is approximately equivalent to the amount of liquid necessary to form the thin film on each face of the slide. This amount can be as little as 1 cc. When sealed, the container is rendered tamperproof so that the contents cannot be adulterated prior to use, thus preventing a false reading of the stained slide. When the stained slide is vertically withdrawn from the chamber, the staining liquid drains off the slide and returns to a pool at the bottom of the chamber. The container and used liquid can then be reused or disposed of. The slide may be inserted and withdrawn from the chamber, and subsequently handled by a portion of the slide which continuously extends above the chamber.
Substantially less staining liquid is required than in the prior art; a fresh batch of reagent is provided for each specimen; sinks are not stained since the liquid remains within the chamber; the operator's fingers do not become stained, since the staining liquid remains within the chamber; and, since the stain is prepackaged, the method is quicker and more time efficient.
The container has a cover or stopper which seals the chamber and the liquid therein prior to use of the container. The container is rendered tamperproof giving assurance that the staining process will yield a true result. After the staining is complete, the chamber may be easily resealed to avoid any subsequent spattering or leakage of staining liquid from the chamber.